The rod bipolar cell (RBC) is a mammalian specialization dedicated to the processing of rod signals. As the first neuron in a position to receive input from a pool of rod photoreceptors, it is expected to play a key role in defining the capabilities of the rod visual system. One primary goal of this project is to establish the role of RBCs in setting the gain, temporal characteristics, threshold behavior and signal-to-noise characteristics of the mammalian visual system. Toward this end the adaptation properties, as well as the small signal and noise properties, of the RBCs will be studied using patch electrode recording techniques. In addition, suction electrodes will be used to study rods, so that the transfer characteristics of the rod/RBC synapse may be established. Recent advances in understanding electroretinograms (ERGs) may make it possible to evaluate RBC function noninvasively with ERGs. Because of this exciting possibility, a second primary goal of this project is to directly compare the light responses of RBCs with the purported RBC signals derived from the ERG.